1 /*
2 * Copyright (c) 2019, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include <classfile/fieldLayoutBuilder.hpp>
26 #include "precompiled.hpp"
27 #include "jvm.h"
28 #include "classfile/classFileParser.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "oops/array.hpp"
31 #include "oops/instanceMirrorKlass.hpp"
32 #include "oops/valueKlass.hpp"
33 #include "runtime/fieldDescriptor.inline.hpp"
34
35 RawBlock::RawBlock(Kind kind, int size, int alignment) {
36 _next_field = NULL;
37 _prev_field = NULL;
38 _next_block = NULL;
39 _prev_block = NULL;
40 _field_index = -1; // no field
41 assert(kind != REGULAR && kind != FLATTENED,
42 "Otherwise, should use the constructor with a field index argument");
43 _kind = kind;
44 _size = size;
45 _alignment = alignment;
46 _offset = -1;
47 _is_reference = false;
48 _value_klass = NULL;
49 assert(_alignment > 0, "Sanity check");
50 }
51
52 RawBlock::RawBlock(int index, Kind kind, int size, int alignment, bool is_reference) {
53 _next_field = NULL;
54 _prev_field = NULL;
55 _next_block = NULL;
56 _prev_block = NULL;
57 _field_index = index;
58 assert(kind == REGULAR || kind == FLATTENED || kind == INHERITED,
59 "Other kind do not have a field index");
60 _kind = kind;
61 _size = size;
62 _alignment = alignment;
63 _offset = -1;
64 _is_reference = is_reference;
65 _value_klass = NULL;
66 assert(_size > 0, "Sanity check");
67 assert(_alignment > 0, "Sanity check");
68 }
69
70 bool RawBlock::fit(int size, int alignment) {
71 int adjustment = _offset % alignment;
72 return _size >= size + adjustment;
73 }
74
75 FieldGroup::FieldGroup(int contended_group) {
76 _next = NULL;
77 _primitive_fields = NULL;
78 _oop_fields = NULL;
79 _flattened_fields = NULL;
80 _contended_group = contended_group; // -1 means no contended group, 0 means default contended group
81 _oop_count = 0;
82 }
83
84 void FieldGroup::add_primitive_field(AllFieldStream fs, BasicType type) {
85 int size = type2aelembytes(type);
86 RawBlock* block = new RawBlock(fs.index(), RawBlock::REGULAR, size, size /* alignment == size for primitive types */, false);
87 add_block(&_primitive_fields, block);
88 }
89
90 void FieldGroup::add_oop_field(AllFieldStream fs) {
91 int size = type2aelembytes(T_OBJECT);
92 RawBlock* block = new RawBlock(fs.index(), RawBlock::REGULAR, size, size /* alignment == size for oops */, true);
93 add_block(&_oop_fields, block);
94 _oop_count++;
95 }
96
97 void FieldGroup::add_flattened_field(AllFieldStream fs, ValueKlass* vk) {
98 // _flattened_fields list might be merged with the _primitive_fields list in the future
99 RawBlock* block = new RawBlock(fs.index(), RawBlock::FLATTENED, vk->get_exact_size_in_bytes(), vk->get_alignment(), false);
100 block->set_value_klass(vk);
101 add_block(&_flattened_fields, block);
102 }
103
104 /* Adds a field to a field group. Inside a field group, fields are sorted by
105 * decreasing sizes. Fields with the same size are sorted according to their
106 * order of insertion (easy hack to respect field order for classes with
107 * hard coded offsets).
108 */
109 void FieldGroup::add_block(RawBlock** list, RawBlock* block) {
110 if (*list == NULL) {
111 *list = block;
112 } else {
113 if (block->size() > (*list)->size()) { // cannot be >= to respect order of field (for classes with hard coded offsets)
114 block->set_next_field(*list);
115 (*list)->set_prev_field(block);
116 *list = block;
117 } else {
118 RawBlock* b = *list;
119 while (b->next_field() != NULL) {
120 if (b->next_field()->size() < block->size()) {
121 break;
122 }
123 b = b->next_field();
124 }
125 block->set_next_field(b->next_field());
126 block->set_prev_field(b);
127 b->set_next_field(block);
128 if (b->next_field() != NULL) {
129 b->next_field()->set_prev_field(block);
130 }
131 }
132 }
133 }
134
135 FieldLayout::FieldLayout(Array<u2>* fields, ConstantPool* cp) {
136 _fields = fields;
137 _cp = cp;
138 _blocks = NULL;
139 _start = _blocks;
140 _last = _blocks;
141 }
142
143 void FieldLayout::initialize_static_layout() {
144 _blocks = new RawBlock(RawBlock::EMPTY, INT_MAX);
145 _blocks->set_offset(0);
146 _last = _blocks;
147 _start = _blocks;
148 // Note: at this stage, InstanceMirrorKlass::offset_of_static_fields() is zero, because
149 // during bootstrapping, the size of the java.lang.Class is still not known when layout
150 // of static field is computed. Field offsets are fixed later when the size is known
151 // (see java_lang_Class::fixup_mirror())
152 insert(first_empty_block(), new RawBlock(RawBlock::RESERVED, InstanceMirrorKlass::offset_of_static_fields()));
153 _blocks->set_offset(0);
154 }
155
156 void FieldLayout::initialize_instance_layout(const InstanceKlass* super_klasss) {
157 if (super_klasss == NULL) {
158 _blocks = new RawBlock(RawBlock::EMPTY, INT_MAX);
159 _blocks->set_offset(0);
160 _last = _blocks;
161 _start = _blocks;
162 insert(first_empty_block(), new RawBlock(RawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes()));
163 } else {
164 // The JVM could reconstruct the layouts of the super classes, in order to use the
165 // empty slots in these layouts to allocate current class' fields. However, some codes
166 // in the JVM are not ready yet to find fields allocated this way, so the optimization
167 // is not enabled yet.
168 #if 0
169 reconstruct_layout(super_klasss);
170 fill_holes(super_klasss);
171 // _start = _last; // uncomment to fill holes in super classes layouts
172 #else
173 _blocks = new RawBlock(RawBlock::EMPTY, INT_MAX);
174 _blocks->set_offset(0);
175 _last = _blocks;
176 insert(_last, new RawBlock(RawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes()));
177 if (super_klasss->nonstatic_field_size() > 0) {
178 // To take into account the space allocated to super classes' fields, this code
179 // uses the nonstatic_field_size() value to allocate a single INHERITED RawBlock.
180 // The drawback is that nonstatic_field_size() expresses the size of non-static
181 // fields in heapOopSize, which implies that some space could be lost at the
182 // end because of the rounding up of the real size. Using the exact size, with
183 // no rounding up, would be possible, but would require modifications to other
184 // codes in the JVM performing fields lookup (as they often expect this rounding
185 // to be applied).
186 RawBlock* inherited = new RawBlock(RawBlock::INHERITED,
187 super_klasss->nonstatic_field_size() * heapOopSize);
188 insert(_last, inherited);
189 }
190 _start = _last;
191 #endif
192 }
193 }
194
195 RawBlock* FieldLayout::first_field_block() {
196 RawBlock* block = _start;
197 // Not sure the condition below will work well when inheriting layout with contented padding
198 while (block->kind() != RawBlock::INHERITED && block->kind() != RawBlock::REGULAR
199 && block->kind() != RawBlock::FLATTENED && block->kind() != RawBlock::PADDING) {
200 block = block->next_block();
201 }
202 return block;
203 }
204
205 /* The allocation logic uses a first fit strategy: the field is allocated in the
206 * first empty slot big enough to contain it (including padding to fit alignment
207 * constraints).
208 */
209 void FieldLayout::add(RawBlock* blocks, RawBlock* start) {
210 if (start == NULL) {
211 // start = this->_blocks;
212 start = this->_start;
213 }
214 RawBlock* b = blocks;
215 RawBlock* candidate = NULL;
216 while (b != NULL) {
217 RawBlock* candidate = start;
218 while (candidate->kind() != RawBlock::EMPTY || !candidate->fit(b->size(), b->alignment())) candidate = candidate->next_block();
219 assert(candidate != NULL && candidate->fit(b->size(), b->alignment()), "paranoid check");
220 insert_field_block(candidate, b);
221 b = b->next_field();
222 }
223 }
224
225 /* The allocation logic uses a first fit strategy: the set of fields is allocated
226 * in the first empty slot big enough to contain the whole set ((including padding
227 * to fit alignment constraints).
228 */
229 void FieldLayout::add_contiguously(RawBlock* blocks, RawBlock* start) {
230 if (blocks == NULL) return;
231 if (start == NULL) {
232 start = _start;
233 }
234 // This code assumes that if the first block is well aligned, the following
235 // blocks would naturally be well aligned (no need for adjustment)
236 int size = 0;
237 RawBlock* b = blocks;
238 while (b != NULL) {
239 size += b->size();
240 b = b->next_field();
241 }
242 RawBlock* candidate = start;
243 while (candidate->kind() != RawBlock::EMPTY || !candidate->fit(size, blocks->alignment())) candidate = candidate->next_block();
244 b = blocks;
245 while (b != NULL) {
246 insert_field_block(candidate, b);
247 b = b->next_field();
248 assert(b == NULL || (candidate->offset() % b->alignment() == 0), "Contiguous blocks must be naturally well aligned");
249 }
250 }
251
252 RawBlock* FieldLayout::insert_field_block(RawBlock* slot, RawBlock* block) {
253 assert(slot->kind() == RawBlock::EMPTY, "Blocks can only be inserted in empty blocks");
254 if (slot->offset() % block->alignment() != 0) {
255 int adjustment = block->alignment() - (slot->offset() % block->alignment());
256 RawBlock* adj = new RawBlock(RawBlock::EMPTY, adjustment);
257 insert(slot, adj);
258 }
259 insert(slot, block);
260 if (slot->size() == 0) {
261 remove(slot);
262 }
263 if (UseNewLayout) {
264 FieldInfo::from_field_array(_fields, block->field_index())->set_offset(block->offset());
265 }
266 return block;
267 }
268
269 void FieldLayout::reconstruct_layout(const InstanceKlass* ik) {
270 // TODO: it makes no sense to support static fields, static fields go to
271 // the mirror, and are not impacted by static fields of the parent class
272 if (ik->super() != NULL) {
273 reconstruct_layout(InstanceKlass::cast(ik->super()));
274 } else {
275 _blocks = new RawBlock(RawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes());
276 _blocks->set_offset(0);
277 _last = _blocks;
278 _start = _blocks;
279 }
280 for (AllFieldStream fs(ik->fields(), ik->constants()); !fs.done(); fs.next()) {
281 BasicType type = vmSymbols::signature_type(fs.signature());
282 // distinction between static and non-static fields is missing
283 if (fs.access_flags().is_static()) continue;
284 ik->fields_annotations();
285 if (type != T_VALUETYPE) {
286 int size = type2aelembytes(type);
287 // INHERITED blocs are marked as non-reference because oop_maps are handled by their holder class
288 RawBlock* block = new RawBlock(fs.index(), RawBlock::INHERITED, size, size, false);
289 block->set_offset(fs.offset());
290 insert_per_offset(block);
291 } else {
292 fatal("Not supported yet");
293 }
294 }
295 }
296
297 void FieldLayout::fill_holes(const InstanceKlass* super_klass) {
298 assert(_blocks != NULL, "Sanity check");
299 assert(_blocks->offset() == 0, "first block must be at offset zero");
300 RawBlock* b = _blocks;
301 while (b->next_block() != NULL) {
302 if (b->next_block()->offset() > (b->offset() + b->size())) {
303 int size = b->next_block()->offset() - (b->offset() + b->size());
304 RawBlock* empty = new RawBlock(RawBlock::EMPTY, size);
305 empty->set_offset(b->offset() + b->size());
306 empty->set_next_block(b->next_block());
307 b->next_block()->set_prev_block(empty);
308 b->set_next_block(empty);
309 empty->set_prev_block(b);
310 }
311 b = b->next_block();
312 }
313 assert(b->next_block() == NULL, "Invariant at this point");
314 if (b->kind() != RawBlock::EMPTY) {
315 RawBlock* last = new RawBlock(RawBlock::EMPTY, INT_MAX);
316 last->set_offset(b->offset() + b->size());
317 assert(last->offset() > 0, "Sanity check");
318 b->set_next_block(last);
319 last->set_prev_block(b);
320 _last = last;
321 }
322 // Still doing the padding to have a size that can be expressed in heapOopSize
323 int super_end = instanceOopDesc::base_offset_in_bytes() + super_klass->nonstatic_field_size() * heapOopSize;
324 if (_last->offset() < super_end) {
325 RawBlock* padding = new RawBlock(RawBlock::PADDING, super_end - _last->offset());
326 insert(_last, padding);
327 }
328 }
329
330 RawBlock* FieldLayout::insert(RawBlock* slot, RawBlock* block) {
331 assert(slot->kind() == RawBlock::EMPTY, "Blocks can only be inserted in empty blocks");
332 assert(slot->offset() % block->alignment() == 0, "Incompatible alignment");
333 block->set_offset(slot->offset());
334 slot->set_offset(slot->offset() + block->size());
335 slot->set_size(slot->size() - block->size());
336 block->set_prev_block(slot->prev_block());
337 block->set_next_block(slot);
338 slot->set_prev_block(block);
339 if (block->prev_block() != NULL) { // suspicious test
340 block->prev_block()->set_next_block(block);
341 }
342 if (_blocks == slot) {
343 _blocks = block;
344 }
345 if (_start == slot) {
346 _start = block;
347 }
348 return block;
349 }
350
351 void FieldLayout::insert_per_offset(RawBlock* block) {
352 if (_blocks == NULL) {
353 _blocks = block;
354 } else if (_blocks->offset() > block->offset()) {
355 block->set_next_block(_blocks);
356 _blocks->set_prev_block(block);
357 _blocks = block;
358 } else {
359 RawBlock* b = _blocks;
360 while (b->next_block() != NULL && b->next_block()->offset() < block->offset()) b = b->next_block();
361 if (b->next_block() == NULL) {
362 b->set_next_block(block);
363 block->set_prev_block(b);
364 } else {
365 assert(b->next_block()->offset() >= block->offset(), "Sanity check");
366 assert(b->next_block()->offset() > block->offset() || b->next_block()->kind() == RawBlock::EMPTY, "Sanity check");
367 block->set_next_block(b->next_block());
368 b->next_block()->set_prev_block(block);
369 block->set_prev_block(b);
370 b->set_next_block(block);
371 }
372 }
373 }
374
375 void FieldLayout::remove(RawBlock* block) {
376 assert(block != NULL, "Sanity check");
377 assert(block != _last, "Sanity check");
378 if (_blocks == block) {
379 _blocks = block->next_block();
380 if (_blocks != NULL) {
381 _blocks->set_prev_block(NULL);
382 }
383 } else {
384 assert(block->prev_block() != NULL, "_prev should be set for non-head blocks");
385 block->prev_block()->set_next_block(block->next_block());
386 block->next_block()->set_prev_block(block->prev_block());
387 }
388 if (block == _start) {
389 _start = block->prev_block();
390 }
391 }
392
393 void FieldLayout::print(outputStream* output) {
394 ResourceMark rm;
395 RawBlock* b = _blocks;
396 while(b != _last) {
397 switch(b->kind()) {
398 case RawBlock::REGULAR: {
399 FieldInfo* fi = FieldInfo::from_field_array(_fields, b->field_index());
400 output->print_cr(" %d %s %d %d %s %s",
401 b->offset(),
402 "REGULAR",
403 b->size(),
404 b->alignment(),
405 fi->signature(_cp)->as_C_string(),
406 fi->name(_cp)->as_C_string());
407 break;
408 }
409 case RawBlock::FLATTENED: {
410 FieldInfo* fi = FieldInfo::from_field_array(_fields, b->field_index());
411 output->print_cr(" %d %s %d %d %s %s",
412 b->offset(),
413 "FLATTENED",
414 b->size(),
415 b->alignment(),
416 fi->signature(_cp)->as_C_string(),
417 fi->name(_cp)->as_C_string());
418 break;
419 }
420 case RawBlock::RESERVED:
421 output->print_cr(" %d %s %d",
422 b->offset(),
423 "RESERVED",
424 b->size());
425 break;
426 case RawBlock::INHERITED:
427 output->print_cr(" %d %s %d",
428 b->offset(),
429 "INHERITED",
430 b->size());
431 break;
432 case RawBlock::EMPTY:
433 output->print_cr(" %d %s %d",
434 b->offset(),
435 "EMPTY",
436 b->size());
437 break;
438 case RawBlock::PADDING:
439 output->print_cr(" %d %s %d",
440 b->offset(),
441 "PADDING",
442 b->size());
443 break;
444 }
445 b = b->next_block();
446 }
447 }
448
449
450 FieldLayoutBuilder::FieldLayoutBuilder(ClassFileParser* cfp, FieldLayoutInfo* info) {
451 _cfp = cfp;
452 _info = info;
453 _fields = NULL;
454 _root_group = NULL;
455 _contended_groups = NULL;
456 _static_fields = NULL;
457 _layout = NULL;
458 _static_layout = NULL;
459 _nonstatic_oopmap_count = 0;
460 // Inline class specific information
461 _alignment = -1;
462 _first_field_offset = -1;
463 _exact_size_in_bytes = -1;
464 _has_nonstatic_fields = false;
465 _has_flattening_information = _cfp->is_value_type();
466 }
467
468 FieldGroup* FieldLayoutBuilder::get_contended_group(int g) {
469 assert(g>0, "must only be called for named contended groups");
470 if (_contended_groups == NULL) {
471 _contended_groups = new FieldGroup(g);
472 return _contended_groups;
473 }
474 FieldGroup* group = _contended_groups;
475 while(group->next() != NULL) {
476 if (group->contended_group() == g) break;
477 group = group->next();
478 }
479 if (group->contended_group() == g) return group;
480 group->set_next(new FieldGroup(g));
481 return group->next();
482 }
483
484 void FieldLayoutBuilder::prologue() {
485 _layout = new FieldLayout(_cfp->_fields, _cfp->_cp);
486 const InstanceKlass* super_klass = _cfp->_super_klass;
487 _layout->initialize_instance_layout(super_klass);
488 if (super_klass != NULL) {
489 _has_nonstatic_fields = super_klass->has_nonstatic_fields();
490 }
491 _static_layout = new FieldLayout(_cfp->_fields, _cfp->_cp);
492 _static_layout->initialize_static_layout();
493 _static_fields = new FieldGroup();
494 _root_group = new FieldGroup();
495 _contended_groups = NULL;
496 }
497
498 /* Field sorting for regular (non-inline) classes:
499 * - fields are sorted in static and non-static fields
500 * - non-static fields are also sorted according to their contention group
501 * (support of the @Contended annotation)
502 * - @Contended annotation is ignored for static fields
503 * - field flattening decisions are taken in this method
504 */
505 void FieldLayoutBuilder::regular_field_sorting(TRAPS) {
506 assert(!_cfp->is_value_type(), "Should only be used for non-inline classes");
507 for (AllFieldStream fs(_cfp->_fields, _cfp->_cp); !fs.done(); fs.next()) {
508 FieldGroup* group = NULL;
509 if (fs.access_flags().is_static()) {
510 group = _static_fields;
511 } else {
512 _has_nonstatic_fields = true;
513 if (fs.is_contended()) {
514 int g = fs.contended_group();
515 if (g == 0) {
516 // default group means the field is alone in its contended group
517 group = new FieldGroup(true);
518 group->set_next(_contended_groups);
519 _contended_groups = group;
520 } else {
521 group = get_contended_group(g);
522 }
523 } else {
524 group = _root_group;
525 }
526 }
527 assert(group != NULL, "invariant");
528 BasicType type = vmSymbols::signature_type(fs.signature());
529 switch(type) {
530 case T_BYTE:
531 case T_CHAR:
532 case T_DOUBLE:
533 case T_FLOAT:
534 case T_INT:
535 case T_LONG:
536 case T_SHORT:
537 case T_BOOLEAN:
538 group->add_primitive_field(fs, type);
539 break;
540 case T_OBJECT:
541 case T_ARRAY:
542 if (group != _static_fields) _nonstatic_oopmap_count++;
543 group->add_oop_field(fs);
544 break;
545 case T_VALUETYPE: {
546 if (group == _static_fields) {
547 // static fields are never flattened
548 group->add_oop_field(fs);
549 } else {
550 _has_flattening_information = true;
551 // Flattening decision to be taken here
552 // This code assumes all verification have been performed before
553 // (field is a flattenable field, field's type has been loaded
554 // and it is an inline klass
555 Klass* klass =
556 SystemDictionary::resolve_flattenable_field_or_fail(&fs,
557 Handle(THREAD, _cfp->_loader_data->class_loader()),
558 _cfp->_protection_domain, true, CHECK);
559 assert(klass != NULL, "Sanity check");
560 ValueKlass* vk = ValueKlass::cast(klass);
561 bool flattened = (ValueFieldMaxFlatSize < 0)
562 || (vk->size_helper() * HeapWordSize) <= ValueFieldMaxFlatSize;
563 if (flattened) {
564 group->add_flattened_field(fs, vk);
565 _nonstatic_oopmap_count += vk->nonstatic_oop_map_count();
566 fs.set_flattened(true);
567 } else {
568 _nonstatic_oopmap_count++;
569 group->add_oop_field(fs);
570 }
571 }
572 break;
573 }
574 default:
575 fatal("Something wrong?");
576 }
577 }
578 }
579 /* Field sorting for inline classes:
580 * - because inline classes are immutable, the @Contended annotation is ignored
581 * when computing their layout (with only read operation, there's no false
582 * sharing issue)
583 * - this method also records the alignment of the field with the most
584 * constraining alignment, this value is then used as the alignment
585 * constraint when flattening this inline type into another container
586 * - field flattening decisions are taken in this method (those decisions are
587 * currently only based in the size of the fields to be flattened, the size
588 * of the resulting instance is not considered)
589 */
590 void FieldLayoutBuilder::inline_class_field_sorting(TRAPS) {
591 assert(_cfp->is_value_type(), "Should only be used for inline classes");
592 int alignment = 1;
593 for (AllFieldStream fs(_cfp->_fields, _cfp->_cp); !fs.done(); fs.next()) {
594 FieldGroup* group = NULL;
595 int field_alignment = 1;
596 if (fs.access_flags().is_static()) {
597 group = _static_fields;
598 } else {
599 _has_nonstatic_fields = true;
600 group = _root_group;
601 }
602 assert(group != NULL, "invariant");
603 BasicType type = vmSymbols::signature_type(fs.signature());
604 switch(type) {
605 case T_BYTE:
606 case T_CHAR:
607 case T_DOUBLE:
608 case T_FLOAT:
609 case T_INT:
610 case T_LONG:
611 case T_SHORT:
612 case T_BOOLEAN:
613 if (group != _static_fields) {
614 field_alignment = type2aelembytes(type); // alignment == size for primitive types
615 }
616 group->add_primitive_field(fs, type);
617 break;
618 case T_OBJECT:
619 case T_ARRAY:
620 if (group != _static_fields) {
621 _nonstatic_oopmap_count++;
622 field_alignment = type2aelembytes(type); // alignment == size for oops
623 }
624 group->add_oop_field(fs);
625 break;
626 case T_VALUETYPE: {
627 if (group == _static_fields) {
628 // static fields are never flattened
629 group->add_oop_field(fs);
630 } else {
631 // Flattening decision to be taken here
632 // This code assumes all verifications have been performed before
633 // (field is a flattenable field, field's type has been loaded
634 // and it is an inline klass
635 Klass* klass =
636 SystemDictionary::resolve_flattenable_field_or_fail(&fs,
637 Handle(THREAD, _cfp->_loader_data->class_loader()),
638 _cfp->_protection_domain, true, CHECK);
639 assert(klass != NULL, "Sanity check");
640 ValueKlass* vk = ValueKlass::cast(klass);
641 bool flattened = (ValueFieldMaxFlatSize < 0)
642 || (vk->size_helper() * HeapWordSize) <= ValueFieldMaxFlatSize;
643 if (flattened) {
644 group->add_flattened_field(fs, vk);
645 _nonstatic_oopmap_count += vk->nonstatic_oop_map_count();
646 field_alignment = vk->get_alignment();
647 fs.set_flattened(true);
648 } else {
649 _nonstatic_oopmap_count++;
650 field_alignment = type2aelembytes(T_OBJECT);
651 group->add_oop_field(fs);
652 }
653 }
654 break;
655 }
656 default:
657 fatal("Unexpected BasicType");
658 }
659 if (!fs.access_flags().is_static() && field_alignment > alignment) alignment = field_alignment;
660 }
661 _alignment = alignment;
662 if (_cfp->is_value_type() && (!_has_nonstatic_fields)) {
663 // There are a number of fixes required throughout the type system and JIT
664 _cfp->throwValueTypeLimitation(THREAD_AND_LOCATION, "Value Types do not support zero instance size yet");
665 return;
666 }
667 }
668
669 /* Computation of regular classes layout is an evolution of the previous default layout
670 * (FieldAllocationStyle 1):
671 * - flattened fields are allocated first (because they have potentially the
672 * least regular shapes, and are more likely to create empty slots between them,
673 * which can then be used to allocation primitive or oop fields). Allocation is
674 * performed from the biggest to the smallest flattened field.
675 * - then primitive fields (from the biggest to the smallest)
676 * - then oop fields are allocated contiguously (to reduce the number of oopmaps
677 * and reduce the work of the GC).
678 */
679 void FieldLayoutBuilder::compute_regular_layout(TRAPS) {
680 bool need_tail_padding = false;
681 prologue();
682 regular_field_sorting(CHECK);
683 const bool is_contended_class = _cfp->_parsed_annotations->is_contended();
684 if (is_contended_class) {
685 RawBlock* padding = new RawBlock(RawBlock::PADDING, ContendedPaddingWidth);
686 // insertion is currently easy because the current strategy doesn't try to fill holes
687 // in super classes layouts => the _start block is by consequence the _last_block
688 _layout->insert(_layout->start(), padding);
689 need_tail_padding = true;
690 }
691 _layout->add(_root_group->flattened_fields());
692 _layout->add(_root_group->primitive_fields());
693 _layout->add_contiguously(_root_group->oop_fields());
694 FieldGroup* cg = _contended_groups;
695 while (cg != NULL) {
696 RawBlock* start = _layout->last_block();
697 RawBlock* padding = new RawBlock(RawBlock::PADDING, ContendedPaddingWidth);
698 _layout->insert(start, padding);
699 _layout->add(cg->flattened_fields(), start);
700 _layout->add(cg->primitive_fields(), start);
701 _layout->add(cg->oop_fields(), start);
702 need_tail_padding = true;
703 cg = cg->next();
704 }
705 if (need_tail_padding) {
706 RawBlock* padding = new RawBlock(RawBlock::PADDING, ContendedPaddingWidth);
707 _layout->insert(_layout->last_block(), padding);
708 }
709 _static_layout->add_contiguously(this->_static_fields->oop_fields());
710 _static_layout->add(this->_static_fields->primitive_fields());
711
712 epilogue();
713 }
714
715 /* Computation of inline classes has a slightly different strategy than for
716 * regular classes. Regular classes have their oop fields allocated at the end
717 * of the layout to increase GC performances. Unfortunately, this strategy
718 * increases the number of empty slots inside an instance. Because the purpose
719 * of inline classes is to be embedded into other containers, it is critical
720 * to keep their size as small as possible. For this reason, the allocation
721 * strategy is:
722 * - flattened fields are allocated first (because they have potentially the
723 * least regular shapes, and are more likely to create empty slots between them,
724 * which can then be used to allocation primitive or oop fields). Allocation is
725 * performed from the biggest to the smallest flattened field.
726 * - then oop fields are allocated contiguously (to reduce the number of oopmaps
727 * and reduce the work of the GC)
728 * - then primitive fields (from the biggest to the smallest)
729 */
730 void FieldLayoutBuilder::compute_inline_class_layout(TRAPS) {
731 prologue();
732 inline_class_field_sorting(CHECK);
733 if (_layout->start()->offset() % _alignment != 0) {
734 RawBlock* padding = new RawBlock(RawBlock::PADDING, _alignment - (_layout->start()->offset() % _alignment));
735 _layout->insert(_layout->start(), padding);
736 _layout->set_start(padding->next_block());
737 }
738 _first_field_offset = _layout->start()->offset();
739 _layout->add(_root_group->flattened_fields());
740 _layout->add_contiguously(_root_group->oop_fields());
741 _layout->add(_root_group->primitive_fields());
742 _exact_size_in_bytes = _layout->last_block()->offset() - _layout->start()->offset();
743
744 _static_layout->add_contiguously(this->_static_fields->oop_fields());
745 _static_layout->add(this->_static_fields->primitive_fields());
746
747 epilogue();
748 }
749
750 void FieldLayoutBuilder::epilogue() {
751 // Computing oopmaps
752 int super_oop_map_count = (_cfp->_super_klass == NULL) ? 0 :_cfp->_super_klass->nonstatic_oop_map_count();
753 int max_oop_map_count = super_oop_map_count + _nonstatic_oopmap_count;
754
755 OopMapBlocksBuilder* nonstatic_oop_maps =
756 new OopMapBlocksBuilder(max_oop_map_count, Thread::current());
757 if (super_oop_map_count > 0) {
758 nonstatic_oop_maps->initialize_inherited_blocks(_cfp->_super_klass->start_of_nonstatic_oop_maps(),
759 _cfp->_super_klass->nonstatic_oop_map_count());
760 }
761 if (_root_group->oop_fields() != NULL) {
762 nonstatic_oop_maps->add(_root_group->oop_fields()->offset(), _root_group->oop_count());
763 }
764 RawBlock* ff = _root_group->flattened_fields();
765 while (ff != NULL) {
766 ValueKlass* vklass = ff->value_klass();
767 assert(vklass != NULL, "Should have been initialized");
768 if (vklass->contains_oops()) { // add flatten oop maps
769 int diff = ff->offset() - vklass->first_field_offset();
770 const OopMapBlock* map = vklass->start_of_nonstatic_oop_maps();
771 const OopMapBlock* const last_map = map + vklass->nonstatic_oop_map_count();
772 while (map < last_map) {
773 nonstatic_oop_maps->add(map->offset() + diff, map->count());
774 map++;
775 }
776 }
777 ff = ff->next_field();
778 }
779 FieldGroup* cg = _contended_groups;
780 while (cg != NULL) {
781 if (cg->oop_count() > 0) {
782 nonstatic_oop_maps->add(cg->oop_fields()->offset(), cg->oop_count());
783 }
784 RawBlock* ff = cg->flattened_fields();
785 while (ff != NULL) {
786 ValueKlass* vklass = ff->value_klass();
787 assert(vklass != NULL, "Should have been initialized");
788 if (vklass->contains_oops()) { // add flatten oop maps
789 int diff = ff->offset() - vklass->first_field_offset();
790 const OopMapBlock* map = vklass->start_of_nonstatic_oop_maps();
791 const OopMapBlock* const last_map = map + vklass->nonstatic_oop_map_count();
792 while (map < last_map) {
793 nonstatic_oop_maps->add(map->offset() + diff, map->count());
794 map++;
795 }
796 }
797 ff = ff->next_field();
798 }
799 cg = cg->next();
800 }
801
802 // nonstatic_oop_maps->compact(Thread::current());
803
804 int instance_end = align_up(_layout->last_block()->offset(), wordSize);
805 int static_fields_end = align_up(_static_layout->last_block()->offset(), wordSize);
806 int static_fields_size = (static_fields_end -
807 InstanceMirrorKlass::offset_of_static_fields()) / wordSize;
808 int nonstatic_field_end = align_up(_layout->last_block()->offset(), heapOopSize);
809
810 // Pass back information needed for InstanceKlass creation
811
812 _info->oop_map_blocks = nonstatic_oop_maps;
813 _info->instance_size = align_object_size(instance_end / wordSize);
814 _info->static_field_size = static_fields_size;
815 _info->nonstatic_field_size = (nonstatic_field_end - instanceOopDesc::base_offset_in_bytes()) / heapOopSize;
816 _info->has_nonstatic_fields = _has_nonstatic_fields;
817
818 if (PrintNewLayout || (PrintFlattenableLayouts && _has_flattening_information)) {
819 ResourceMark rm;
820 tty->print_cr("Layout of class %s", _cfp->_class_name->as_C_string());
821 tty->print_cr("|offset|kind|size|alignment|signature|name|");
822 tty->print_cr("Instance fields:");
823 _layout->print(tty);
824 tty->print_cr("Static fields");
825 _static_layout->print(tty);
826 nonstatic_oop_maps->print_on(tty);
827 tty->print_cr("Instance size = %d * heapWordSize", _info->instance_size);
828 tty->print_cr("Non-static field size = %d * heapWordSize", _info->nonstatic_field_size);
829 tty->print_cr("Static field size = %d * heapWordSize", _info->static_field_size);
830 if (_cfp->is_value_type()) {
831 tty->print_cr("alignment = %d", _alignment);
832 tty->print_cr("exact_size_in_bytes = %d", _exact_size_in_bytes);
833 tty->print_cr("first_field_offset = %d", _first_field_offset);
834 }
835 tty->print_cr("---");
836 }
837 }